Electrocoagulation process in water treatment: A review of electrocoagulation modeling approaches

Hakizimana, Jean Népo; Gourich, Bouchaib; Chafi, Mohammed; Stiriba, Youssef; Vial, Christophe; Drogui, Patrick; Naja, Jamal

doi:10.1016/j.desal.2016.10.011

Cited by 671 publications

(318 citation statements)

References 122 publications

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“…For the rest of the tests, the final pH was < 4 after adding a dose of iron equivalent to that dosed electrochemically, due to the formation of iron (III) hydroxide by means of Eqn , among other iron species of dissimilar solubility [e.g. Fe(OH) 2 , Fe(OH) 3 − ] . All of these reactions result in the formation of H + and thus reduce the pH of the solution.…”

Section: Resultsmentioning

confidence: 97%

Development of a novel electrochemical coagulant dosing unit for water treatment

Llanos

Isidro

Sáez

et al. 2018

J of Chemical Tech & Biotech

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BACKGROUND The design of new approaches that help to decrease both the environmental impact of industrial activities and the cost of existing water treatment technologies is becoming a key aspect of research. In the present work, an efficient and easy‐to‐use electrochemical device designed to dose iron coagulants is presented. RESULTS The proposed device (the Electrochemically‐assisted Coagulant – production & dosing Unit, ECU) exhibits an efficient performance in the dosing of coagulants regardless of the ionic conductivity of the water matrixes tested (within the range 100 to 1000 µS cm−1), covering a wide range of potential real surface waters. The behaviour of the ECU device was compared to that of a conventional chemical dosing of iron, and showed better pH (pH ≈ 8 for ECU but < 4 for equivalent chemical dosing) and conductivity (decrease for ECU but increase up to 60% for equivalent chemical dosing) control. Moreover, the ECU unit produced a noticeable amount of Fe2+ ions, due to the limited access of atmospheric oxygen inside the device. CONLUSION The device developed overcomes traditional chemical iron dosing and could be potentially applied in uses different from electrocoagulation, as it is the case of Fenton‐related technologies. © 2018 Society of Chemical Industry

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Section: Resultsmentioning

confidence: 97%

Development of a novel electrochemical coagulant dosing unit for water treatment

Llanos

Isidro

Sáez

et al. 2018

J of Chemical Tech & Biotech

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“…This includes the removing of oxygen atoms, hydrogen atoms, or electrons involves in many oxidation and reduction process (redox). [15] Zinc is known as a good reducing agent and needs to lose an electron that requires the electron transfer. In addition, the reducing agent zinc oxidized and donated the electrons to the oxidizing agents.…”

Section: Resultsmentioning

confidence: 99%

The Treatment of Landfill Leachate by Electrocoagulation to Reduce Heavy Metals and Ammonia-Nitrogen

Kasmuri

Tarmizi

2018

IJET

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Landfill leachate contains high concentration of contaminants in the form of nitrogen, suspended solids and heavy metals, which effects the environment adversely. Hence leachate treatment is considered vital in landfill management as the effluent needs to undergo several treatments before being discharged into natural water bodies. Without treatment, the leachate will contaminate the surface and ground water as it can penetrate through soils and subsoils. Several methods have been applied for the treatment of landfill leachate. However, these methods have several constraints due to area required and cost incurred. This paper presents the application of electrocoagulation in removing pollutants from landfill leachate; particularly ammonia-nitrogen and heavy metals. Three metals namely aluminium, iron and zinc were used as electrodes. Aluminium electrode was found to be the most effective where it was capable to extract 89% of zinc and 75% of iron in 30-minute retention time. Subsequently, 93% of zinc and 83% of iron was removed in 120 minutes. In addition, 93% of ammonia-nitrogen was also removed. These results led to a conclusion that the electrocoagulation had the capacity to remove heavy metals and ammonia-nitrogen present in landfill leachate.

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“…The pH close to the anode surface becomes acidic due to metal hydrolysis while the pH at the cathode increases due to hydroxide formation . The local pH affects the speciation, electrochemistry, and the performance of the process …”

Section: Figurementioning

confidence: 99%

In‐Operando Mapping of pH Distribution in Electrochemical Processes

et al. 2019

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In aqueous electrochemical processes, the pH evolves spatially and temporally, and often dictates the process performance. Herein, a new method for the in‐operando monitoring of pH distribution in an electrochemical cell is demonstrated. A combination of pH‐sensitive fluorescent dyes, encompassing a wide pH range from ≈1.5 to 8.5, and rapid electrochemically coupled laser scanning confocal microscopy is used to observe pH changes in the cell. Using electrocoagulation as an example process, we show that the method provides new insights into the reaction mechanisms. The pH close to the aluminium electrode surface is influenced by the applied current density, hydrolysis of aluminium cations, and gas evolution. Through quantification of the pH at the anode, along with gas analysis, we find that hydrogen is evolved at the anode due to a non‐Faradaic chemical reaction. This leads to increased production of coagulant, which may open new routes to enhance the process performance. This method for in‐operando dynamic visualization of pH paves the way for studies of electrochemical processes, including other water treatment, electrosynthesis, and batteries.

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Electrocoagulation process in water treatment: A review of electrocoagulation modeling approaches

Cited by 671 publications

References 122 publications

Development of a novel electrochemical coagulant dosing unit for water treatment

Development of a novel electrochemical coagulant dosing unit for water treatment

The Treatment of Landfill Leachate by Electrocoagulation to Reduce Heavy Metals and Ammonia-Nitrogen

In‐Operando Mapping of pH Distribution in Electrochemical Processes

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